const fs   = require('fs'),
      file = process.argv[2],
            log  = console.log;

            if(process.argv.length !== 3) {
                console.error('命令行参数格式：cmd fileName');
                  process.exit(1);

            }

            let buf;

try {
    buf = fs.readFileSync(file);

} catch(e) {
    console.error(e.message);
      process.exit(2);

}

if(buf.toString('ascii', 0, 2) === 'BM') {
    log('width:', buf.readInt32LE(0x12));
      log('height:', buf.readInt32LE(0x16));
        log('color depth:', buf.readUInt16LE(0x1c));

}
